Far-IR reflectance study on (Ba<inf>(1-x)</inf>Sr<inf>x</inf>)(Zn<inf>1/3</inf>Ta<inf>2/3</inf>)O<inf>3</inf> dielectric resonators as a function of tolerance factor

The aim of this work is to understand the effect of the tilting of octahedra on polar phonon modes of lattice vibration, which contributes a major part to the dielectric polarization in the crystal. The tolerance factor, which is a measure of the packing of ions in the perovskite unit cell, determines the tilting of oxygen octahedra in the perovskite materials. In this work we have discussed the variation of polar phonon frequencies with respect to the tolerance factor in the composition (Ba(1-x)Srx)(Zn1/3Ta2/3)O3 with x = 0.0, 0.3, 0.5, 0.7, 1.0. The dielectric properties measured at the microwave frequency range are also highlighted to support the ideas proposed in this paper.